Heating apparatus



Oct. 31, 1944. M, U L 2,361,643

HEAT I NG APPARATUS Filed April 20, 1942 2 Sheets-Sheet 1 44 -v--INVENTOR E wail A. Mueller 337% 9/L W 3%TORNEY Oct. 31, 1944. M. L.MUELLER 2,361,643

HEATING APPARATUS Filed April 20, 1942 2 Sheets-Sheet 2 iNVENTOR wrz iz1, MuaZZer: M -Q3, *5

ATTORNEY f Patented Oct. 31, 1944 HEATING APPARATUS Moritz L. Mueller,Seattle, Wash., assignor, by mesne assignments, to Moritz L. Mueller andJohn H. Mueller, Seattle, Wasl1., as joint tenants Application April 20,1942, Serial No. 439,654

17 Claims.

This invention relates to heating apparatus of the type in which thechimney forms at least a part of the heat exchanger.

A principal object of the invention is to provide a novel and lessexpensive construction of heating apparatus of the foregoing type.

Another object .of the invention is to provide a heating system formedof sheet metal in which the chimney which comprises a straight verticalflue is surrounded by a sheet metal jacket along a substantial part ofits length to provide a heat exchanger through which air to be heated iscirculated in counterflow relationship with respect to the flue gases.

Another object of the invention is to provide a compact, very efiicient,and inexpensive form of heating apparatus comprising a unit formedlargely, if not entirely, of sheet metal and which is adapted for use inlow-cost homes, factories, stores, etc., which do not have anybasements, and which heatingapparatus is adapted to be arranged eitheron the floor of the building or suspended from above.

Another object of the invention is to provide a simplified, inexpensivetype of sheet metal furnace construction which is formed integrally withthe chimney and which has comparatively small horizontal dimensionsrelative to the height of the furnace so that very little floor spacetherefor is required.

merit of the heating apparatus illustrated in Fig. 5; I

Fig. 7 is a diagrammatic illustration of the control circuit for themotor of the blower of the unit illustrated in Fig. 6;

Fig. 8 is aview similar to Fig. 6 but illustrating a modified form ofthe invention;

Figs. 9 and 10 are fragmentary views illustrating modifications of Figs.8 and 6 respectively.

Referring now to Figs. 1 to 4, there is illustrated a part of a househaving space to be heated comprising rooms l2 and I4, attic It, a roofI, and no basement. A closet of rectangular form and formed of sheetmetal is supported upon the floor 22 and extends vertically through andabove the ceiling 24. A substantially straight [sheet metal chimney 26having an enlargement Other objects and advantages of the invention willbe apparent from a consideration of the following specification taken inconjunction with the accompanying drawings, of which there are twosheets and wherein:

Fig. 1 is a vertical cross section through a part of a houseillustrating one embodiment of the invention and the air circulationthrough the furnace and the house;

Fig. 2 is a horizontal section taken in a plane along the line 2-2 ofFig. 1, looking in the direction of the arrows;

Fig. 3 is a horizontal section taken along the line 3-3 of Fig. 1,looking in the direction of the arrows;

Fig. 4 is a diagrammatic illustration of a circuit which may be employedfor controlling the operation of the air blower motor;

Fig. 5 is a diagrammatic view of a vertical section through a part Of afactory with a saw-tooth roof and illustrating another embodiment of myinvention employed as a heating apparatus for heating the same;

Fig. 6 is an enlarged elevational view with certain parts illustrated insection of the embodi- 28 at its lower end extends upright to and abovethe roof l8 of the building where it is provided with an atmosphericdischarge. The enlarge.- ment 28 forms a combustion chamber 30 to theupper end of which the lower end of the chimney 26 is connected, thechimney 26 forming a substantially straight flue for conducting theprodnets of combustion from the chamber 30 to atmosphere.

In order to restrict the efiective draft in the combustion chamber 30the chimney may be provided with a draft restricting device comprisingan adjustably mounted plate damper 32 mounted on trunnions and arrangedwithin the chimney 26 a short ways above the combustion chamber 30. Ahandle 34 accessible through a door 36 in the wall of the closet 20 isprovided for adjusting the position of the damper 32.

Inwardly extending spiral vanes 38 carried by the wall of the chimney 26above the damper 32 may be provided for imparting a spiraling motion tothe products of combustion or flue gases in order to promote theexchange of heat through the metal wall of chimney 26. The enlargement28 of the chimney 26 which forms the combustion chamber 30 is supportedby the side walls of the closet 20 a short distance above the floor 22.Th plate 40 within the area enclosed by the enlargement 28 is perforatedso as to provide an air intake opening for admitting air to the fuelburner 42 hereinafter described.

The lower end of the wall of the closet 20 may be cut away as at 44 soas to admit air to the under side of the perforations in the plate 40. vA plate 46 extending transversely of the vertical walls of theenlargement 28 divides the combustion chamber 30 and is provided with anopening 48. A pot burner 42 supported by the plate 46 below opening 48is adapted to burn fuel oil under natural draft, the pot burner 42comprising a common type of heat vaporizing or atmospheric type of oilburner now available on the market.

Oil from a reservoir (not shown) is admitted to the burner 42 under theregulation of a control valve 59 provided with a hand control 52 bymeans of which the rate of fuel feed to the burner may be varied. Theburner 42 at pilot fire will support combustion within the burner 42 butwhen the control 59 has been set to supply oil to the burner at anincreased rate, some of the oil vapors will pass through the opening 48and burn in the combustion chamber 99. The chimney 26 conducts theproducts of combustion from the chamber 39 to atmosphere and due to thefact that the flue passageway formed by the chimney 26 is substantiallystraight, a six-inch diameter pipe will provide sufficiently strongdraft to enable the burner 49 to operate at high efliciency undernatural draft.

A pipe 54 closed at its upper end and arranged around the chimneydefines a path 55 for circulating air in heat exchange relationship withthe chimney 26. The lower end of the pipe 54 is enlarged at 55 in viewof the enlargement 28 of the chimney 26 and terminates a short distanceabove the plate 49. The pipe 54 is arranged between the wall of thecloset 29 and the chimney 26 throughout the entire extent of the closet29 except at the very bottom thereof and cooperates with the wall of thecloset 29 to provide a path 58 for conducting heated air from the lowerend of the enlargement 56 to warm air discharge openings 69, 62, and 64arranged adjacent the ceiling 24. The wall of the closet 29 may beprovided with one or more warm air discharge openings 66 just above theplate 49 for discharging heated air into the space to be heated adjacentthe floor 22 thereof.

At its top the closet 29 is sealed to the pipe 54 which projectsthereabove and the pipe 54 at its top is sealed to the chimney 26 whichprojects thereabove and through the roof l8 of the building. The closet29 maybe said to comprise a plenum chamber which as heretofore indicatedis provided with suitable warm air discharge openings for delivering airto various parts of the space to be heated. The openings 62 and 64 mayhave ducts 68 and 19 connected thereto for conducting the heated air todistant parts of the house.

The path 55 for circulating air inheat exchange relationship with theheat exchange surface provided by the outside of the chimney 26 isprovided with an inlet 12 and means are pro-=- vided for supplying airfrom the space to be heated to such inlet 12, said means comprising acold air return or opening 14 formed in the wall of the space adjacentthe floor 22 thereof and communicating with a duct 76 formed in the wallof the space, a horizontal duct '39 formed between the joists above theceiling 24 and communicating at one end with the upper end of the duct16 and at its other end with a header 89 which through a duct 82 isconnected to the intake side of a forced air circulating means or blower84, the discharge side of which has connected to it a conduit 86 forconducting and delivering air under pressure to the opening 12 at theupper end of the path 55 of the heat exchanger. The blower 84 may bedriven by an electric motor 88 and when so driven is adapted tocirculate air from the space I 4 through the opening 14, ducts l6 andI8, header 89, conduits 82 and 86 through the air path 55 of thefurnace, and thence through the various warm air outlet openings 69, 62,64, 66, 69 to the several parts of the space to be heated.

The upper end of the air path 55 may be provided with an air bleed so asto permit gravity circulation of air upwardly through the path for thepurpose of dissipating heat from the chimney 26 if the blower 88 failsto operate under certain conditions. This bleed comprises a port 99adapted to be closed by a damper 92 pivoted at 94. The port 99 maycomprise an opening formed in the end of a pipe section 96 whichprojects laterally from the elbow at the upper end of the conduit 86.The damper 92 is shown in Fig. 1 in its closed position in full lines,and in its open position in dotted lines.

The end of the pipe section 96 may be provided with a flange 98 whichforms a seat for the damper 92 in its closed position. The airdischarged by the blower 84 during operation thereof will move thedamper from its open to its closed position and the damper is so mountedon the pivot 94 that the damper 92 will remain in its closed positionwhen the blower 84 is not operating, except as hereinafter described.

A thermostatic element I99 mounted on a wall I92 which closes the pipesection 96 below the damper 92 is provided with an arm. B94 which isadapted to engage an arm I96 carried by the damper 92 for moving the endof the arm )6 in the position indicated by the arrow 198, thereby toinitiate opening movement of the damper 92. As soon as the damper 92moves a short distance away from its seat 98, gravity acting on thedamper 92 will move it to the dotted line position where it is held byreason of the fact that the end of the arm I96 will engage the inside ofthe wall I 92 and-act as a stop for limiting opening movement of thedamper. The thermostat I99 is arranged so as to open the damper 92 ifthe temperature of the air in the path 55 and the upper end of theconduit 86 exceeds a predetermined amount, say, for example, 225 F. Thiscondition might arise when the burner 92 is operating at high fire andthe blower 94 fails to operate. When the damper 92 opens, air is free tocirculate upwardly through the path 55 and be vented into the attic l6through the port 99, thereby dissipating heat from the chimney 26 andpreventing overheating of the heating system if the air blower fails tooperate.

The circuit for the blower motor 89 is diagrammatically illustrated inFig. 4 and includes a circuit H9 connected to a suitable source ofcurrent and provided with a normally open switch H2. A rotary cam H4carried by the shaft of the control 59 to which the handle or knob 52.is afllxed is adapted to cooperate with the switch H2 for closing thesame when the handle 52 is turned for the purpose of adjusting the valve59 so as to increase the rate of fuel feed to the burner 52. The control59 may be arranged when the handle 52 is in one position thereof to passonly sufiicient fuel to the burner 42 to support a pilot flame in theburner 42 and combustion chamber 39, andthe cam H9 may be arranged onthe control shaft so that when the burner 42 is operating on pilot flamethe switch 2 will be open. However, as soon as the handle 52 is turnedto increase the fuel feed to the burner 42, the cam H4 will close theswitch H2 and thereby effect operation of the blower 94 and the forcedcirculation of air continuous chimney 26.

surrounded by a pipe I22.

through the heating system as previously described. When the handle 52is subsequently returned to its low or pilot fire position, the

switch H2 will open and discontinue operation through the chimney 26under natural draft and escape to atmosphere through the atmosphericvent at the upper end of the chimne'y:- The air to be heated supplied tothe upper end of the air path 55 flows downwardly through the path 55and in countercurrent heat exchange relationship with the upwardlyflowing flue gases,

and after leaving the path 55 the heated air is discharged through thevariousopenings in the wall of the closet 20.

The chimney 26 may be formed of sections of sheet metal pipe coated withporcelain inside and out to resist corrosion and which are securedtogether so as to provide the vertical The air forced through the path55 by the blower 04 under the discharge pressure thereof is under agreater pressure than the pressure of the flue gases inside the chimney26 in view of the fact that they pass upwardly through the chimney undernatural draft, so that if there is any leakage of the chimney 26 it willbe of air from the path 55 into the chimney 26, thereby avoidingcontamination of the air path 55.

That portion of the chimney 26 and the enlargement 28 thereof surroundedby the pipe 54 forms an elongated vertically arranged heat ex-- changerwhich is of a length in excess of the normal vertical clearance providedin 'a basement or between the floor and ceiling of a room in an averagedwelling. In other words, and as apparent from Fig. 1 of the drawings,the heat exchanger of the furnace extends throughout substantially theentire extent of one floor, through the ceiling thereabove, andmaterially above the ceiling. By reason of this, the floor area requiredfor heating systems of this kind is relatively low as compared withconventional heating systems; for example, in the structure illustratedin Fig. l, the outside dimensions of the closet 20 may be 18 inchessquare, and where the pipe 64 extends approximately four feet above theupper end of the closet 20, a heat output of the system of approximately68,000

B. t. u.s per hour can be obtained where the pipe 54 is ten inches indiameter, and the pipe 26 is six inches in diameter.

In the modifications illustrated in Figs. 5 to inclusive, the heatingsystem illustrated in Fig. l is shown as adapted for heating space in afactory. Referring to Fig. 6, for example, a heating furnace adapted forfactory use may comprise an elongated vertical smoke pipe I The smokepipe or chimney I20 as shown in Fig. 5 is adapted to extend through theroof of the factory building and is provided with an atmosphericdischarge above the roof. The lower end of the chimney or smoke pipe I20has connected thereto a combustion chamber I24 having fuel burning meansindicated generally at I26 associated therewith, the said fuel burningmeans being provided with an air intake opening I28 and being adapted tooperate under natural draft. The fuel burning means I26 may be of thetype illustrated in Fig. l. The pipe I22 as illustrated in Fig. 6surrounds the chimney I20 throughout a substantial portion of itslength, that portion of the chimney I20 surrounded by the pipe I22comprising a heat exchanger. The pipe I22 is open at its bottom so as todeliver air downwardly. The pipe I22 is closed as its top around thechimney I20 and carries a blower I30 driven by electric motor I32. Athermostatic switch I 34 having a thermal element I36 arranged in thechimney I20 just above the pipe I22 is adapted to open and close themotor circuit which is die.-

grammatically illustrated in Fig. 7.

The switch I34 may be set to close the motor circuit when the flue gastemperature passing the element I36 attains a predetermined degree, say,for example, 225 F. and to open the motor circuit when the temperatureof th fiue gases passing the element I36 drops below a predetermineddegree, for example, 200 F. The blower I30 is provided with an intakeand discharges air under pressure into the upper end of the pipe I22 andeffects a downward circulation of air over the heat exchanger surface ofthe chimney I22 and downwardly from the lower open end of the pipe I22.The structure illustrated in Fig. 6 comprises a unit which is adapted tobe suspended in the upper part of space to be heated, for example, asillustrated in Fig. 5, and during operation will take air from the upperpart of such space'and after heating it deliver it downwardly toward thefloor.

The structure illustrated in Fig. 8 is a modification of thatillustrated in Fig. 6 and diifers therefrom in that the air pipe I42 isarranged inside of and in spaced relation with the chimney or smoke pipeI40. The lower end of the pipe I42 terminates in a header I44 providedwith laterally extending outlets I46 projecting through the wall of thepipe I 40 above the combustion chamber I46 therein. The combustionchamber I46 may have the same type of fuel burning means associatedtherewith as illustrated in Fig. 6, and such fuel burning means duringoperation thereof under natural draft generates heated products ofcombustion which pass upwardly through the space between the pipes I42and I40. Above the pipe I42 the smoke pipe I40 may be reduced indiameter as at I50 and project upwardly through the roof to anatmospheric discharge as does the smoke pipe I20 illustrated in Fig. 6.The blower, motor, control and circuit for the motor of the modificationillustrated in Fig. 8 may be the same as that illustrated in Fig. 6, andhence need not be further described. The structure illustrated in Fig. 8comprises a unit similar to that illustrated in Fig. 6 except that inthe case of Fig. 8 the air path is inside of and surrounded by theproducts of combustion, whereas in Fig. 6 the reverse is true. Theoutlets I46 formed in the header I44 may be provided with louvers fordeflecting the warm air downwardly toward the lower part of the space tobe heated.

Figs. 9 and 10 are modifications of Figs. 6 and 8 and illustrate the useof gas burners as the means for burning fuel. As shown in Fig. 9, whichis a modification of Fig. 8, the lower end of the smoke pipe or chimneyis enlarged to provide a combustion chamber I60 in which a gas burnerI62 is arranged. the chamber I60 being provided with an air intakeopening I64 and agas burner I62 being arranged to operate under naturaldraft. Fig. 10, which is a modification of the structure illustrated inFig. 6, may have the lower end of the smoke pipe formed to provide acombustion chamber I60 like that illustrated in Fig. 9 and provided witha gas burner I62 like that illustrated in Fig. 9. Except in theforegoing particulars, the construction and operation of the structuresillustrated in Figs. 9 and 10 are like that of the structuresillustrated in Figs. 8 and 6 respectively.

The fuel burning means illustrated in Figs. 6 and 8 may be provided witha control like that illustrated in Fig. 1, or such fuel burning means,as well as those illustrated in the modifications disclosed in Figs. 9and 10, may be provided with controls as illustrated in my Patent No.2,348,834, granted May 16, 1944.

While the invention has been described with some detail, it isto beunderstood that the description is for th purpose of illustration onlyand is not definitive of the limits of the inventive idea. The right isreserved to make such changes in the details of construction andarrangement of,

partsas will fall within the purview of the attached claims.

The intake for the blower I30 is not shown but is provided on the sideopposite the motor 132 and permits the blower to draw air therethroughfrom the upper end of the space to be heated. As this opening to theblower is not closed and is at the upper end of the path for air throughthe pipes I22 and I46, such blower intake opening will vent heated airfrom the pipes [22 and M when the blower fails to operate in accordancewith th heat output of the fuel burning means.

I claim:

1. A heating system for supplying heated air to a space in a building tobe occupied by and for the comfort of human beings comprising a metallicchimney which extends upright to and above the roof of the building andhas an atmospheric discharge external of the space, a combustion chamberin the lower portion of said chimney, fuel burning means in saidcombustion chamber constructed and arranged for burning fuel undernatural draft operation and functioning to supply heated products ofcombustion to said chimney, said chimney providing a path for flow ofthe combustion products from said combustion chamber to said atmosphericdischarge, a hollow member extending longitudinally of and along asubstantial portion of the length of said chimney and providing aunidirectional single path for how of air in intimate countercurrentheat exchange relationship with the path for flow of the combustionproducts upwardly through said chimney, said air path being providedwith its air inlet at its upper end and its air outlet at its lower endand constructed so that all of the air which enters said path traversessubstantially all of said path and is delivered therefrom at any onetime during operation of said system at a substantially uniformtemperature, a closet in which the lower ends of said hollow member andchimney are arranged and into which heated air is delivered through saidoutlet, the upper end of said hollow member and chimney projecting abovesaid closet, said closet being provided with heated air outlets throughall of which heated air is discharged at substantially the sametemperature into said space, an air blower located outside of saidcloset and operatively connected to said space and to said air inlet inthe upper portion of the hollow member which projects above said closet,said blower being operative to supply from said space to the upper endof said air path, air to be heated and under a pressure greater than thepressure of the products of combustion in said chimney, and means foroperating said blower during operation oi said fuel burning means.

2. A heating system for supplying heated air to a space below a ceilingin a building to be cccupied by and for the comfort of human beingscomprising a metallic chimney which extends upright through the ceilingand to and above the roof of the building and has an atmosphericdischarge external of the space, a combustion chamber in the lowerportion of said chimney, fuel burning means in said combustion chamberconstructed and arranged for burning fuel under natural draft operationand functioning to supply heated products of combustion to said chimney,said chimney providing a substantially straight path for flow of thecombustion products from said combustion chamber to said atmosphericdischarge, a hollow metallic member extending longitudinally of andalong a substantial portion of the length of said chimney and providinga unidirectional uninterrupted path for flow of air in intimatecountercurrent heat exchange relationship with the path for flow of thecombustion products upwardly through said chimney, the lower end of saidhollow member surrounding said combustion chamber, said air path beingprovided with its air inlet at its upper end and its air outlet at itslower end and constructed so that all of the air which enters said pathtraverses substantially all of said path and is delivered therefrom atany one time during operation of said system at a substantially uniformtemperature, a vertically elongated closet in which the lower ends ofsaid hollow member and chimney are arranged and into which heated air isdelivered through said outlet, said closet extending upright at least tothe ceiling of said space, the upper end of said hollow member andchimney projecting above said closet, said closet being provided withheated air outlets through all of which heated air is discharged atsubstantially the same temperature into said space, an air .blowerarranged outside of said closet and said space and operatively connectedto said space and to said air inlet in the upper portion of the hollowmember which projects above said closet, said blower being operative tosupply from said space to the upper end of said air path, air to beheated and under a pressure greater than the pressure of the products ofcombustion, and means for operating said blower during operation of saidfuel burning means.

3. A heating system for supplying heated air to a space in a building tobe occupied by and for the comfort of human beings, said building havinga ceiling above and a floor below said space, said system comprising ametallic chimney supported on said floor and which extends uprightthrough the ceiling and to and above the roof of the building and has anatmospheric discharge external of the space, a combustion chamber in thelower portion of said chimney, fuel burning means in said combustionchamber constructed and arranged for burning fuel under natural draftoperation and functioning to supply heated products of combustion tosaid chimney, said chimney providing a path for flow of the combustionproducts from said combustion chamber to said atmospheric discharge, ahollow tubular member extending longitudinally of and along asubstantial portion of the length of said chimney and providing aunidirectional continuous path for flow of air in intimatecountercurrent heat exchange relationship with the path for flow of thecombustion products upwardly through said chimney, said air path beingprovided with its air inlet at its upper end and its air outlet at itslower end and constructed so that all of the air which enters said pathtraverses substantially all of said path and is delivered therefrom atany one time during operation of said system at a substantially uniformtemperature, a vertically elongated closet in which the lower ends ofsaid hollow member and chimney are arranged and into which heated air isdelivered through said outlet, the upper end of said hollow member andchimney projecting above said closet, said closet being supported onsaid floor and extending above said ceiling and being provided withheated air outlets through all of which heated air is discharged atsubstantially the same temperature into said space, an air blowerarranged outside of said closet and operatively connected to said spaceand to said air inlet in the upper portion of the hollow member whichprojects above said closet, said blower being operative to supply fromsaid space to the upper end of said air path, air to be heated and undera pressure greater than the pressure of the products of combustion, andmeans for operating said blower during operation of said fuel burningmeans.

4. A heating system for supplying heated air to a space in a building tobe occupied by and for the comfort of human beings comprising a metallicchimney which extends upright to and above the roof of the building andhas an atp e i di charge external of the space, a combustion chamber inthe lower portion of said chimney, fuel burning means in said combustionchamber constructed and arranged for burning fuel under natural draftoperation and functioning to supply heated products of combustion tosaid chimney, said chimney providing a path for flow of the combustionproducts from said combustion chamber to said atmospheric discharge. ahollow member extending longitudinally of and along a substantialportion of the length of said chimney and providing a path for flow ofair in intimate countercurrent heat exchange relationship with the pathfor flow of the combustion products upwardly through said chimney, thelower end of said hollow member surrounding said combustion chamber,said air path being provided with its air inlet at its upper end and itsair outlet at its lower end and constructed so that all of the air whichenters said path traverses substantially all of said path and isdelivered therefrom at any one time during opera tion of said system ata substantially uniform temperature. a closet in which the lower ends ofsaid hollow member and chimney are arranged and into which heated air isdelivered through said outlet, the upper end of said chimney projectingabove said closet, said closet being provided with heated air outletsthrough which heated air is d scharged at substantially the sametemperature into said space, an air blower located outside of saidcloset and operatively connected to said space and to said air inlet insaid hollow member, said blower being operative to supply from saidspace to said air path, air to be heated and under a pressure greaterthan the pressure of the products of combustion, means for operatingsaid blower during operation of said fuel burning means above a pilotfire rate, and an air bleed at the upper end of said air path forventing heated air from said air path when said blower fails to operateduring operation of said fuel burning means above a pilot fire rate.

5. A heating system for supplying heated air to a space in a building tobe occupied by and for the comfort of human beings comprising a metallicchimney which extends upright to and above the roof of the building andhas an atmospheric discharge external of the space, a combustion chamberin the lower portion of said chimney, fuel burning means in saidcombustion chamber constructed and arranged for burning fuel undernatural draft operation and functioning to supply heated products ofcombustion to said chimney, said chimney providing a path for flow ofthe combustion products from said combustion chamber to said atmosphericdischarge, a hollow member extending longitudinally of and along asubstantial portion of the length of said chimney and providing aunidirectional path for flow of air in intimate countercurrent heatexchange a relationship with the path for flow of the combustionproducts upwardly through said chimney, said air path being providedwith its air inlet at its upper end and its air outlet at its lower endand constructed so that all of the air which enters said path traversessubstantially all of said path and is delivered therefrom at any onetime during operation of said system at a substantially uniformtemperature, a closet in which the lower ends of said hollow member andchimney are arranged and into which heated air is delivered through saidoutlet, the upper end of said hollow member and chimney projecting abovesaid closets-said closet being provided with heated air outlets throughwhich heated air is discharged at substantially the same temperatureinto said space, an air blower located outside of said closet andoperatively connected to said space and to said air inlet in the upperportion of the hollow member which projects above said closet, saidblower being operative to supply from said space to said air path, airto be heated and under a pressure greater than the pressure of theproducts of combustion, means for operating said blower in accordancewith the heat output of said fuel burning means, and an air bleed at theupper end of said air path for venting heated air from said air pathduring operation of said fuel burning means when said blower fails tooperate in accordance with the heat output of said fuel burning means.

6. A heating system for supplying heated air to a space in a building tobe occupied by and for the comfort of human beings comprising a metallicchimney which extends upright to and above the roof of the building andhas an atmospheric discharge external of the space, a combustion chamberin the lower portion of said chimney, fuel burning means in saidcombustion chamber constructed and arranged for burning fuel undernatural draft operation and'functioning to supply heated products ofcombustion to said chimney, said chimney providing a path for flow ofthe combustion products from said combustion chamber to said atmosphericdischarge, a hollow metallic member extending longitudinally of andalong a substantial portion of the length of said chimney and providinga unidirectional path for flow of air in intimate countercurrent heatexchange relationship with the path for flow of the combustion productsupwardly through said chimney, said air path being provided with its airinlet at its upper end and its air outlet at its lower end andconstructed so that all of the air which enters said path traversessubstantially all of said path and is delivered therefrom at any onetime during operation of said system at a substantially uniformtemperature, a vertically elongated metal closet in which the lower endsof said hollow member and chimney are arranged and into which heated airis delivered through said outlet, the upper end of said hollow' memberand chimney projecting above said closet, said closet being providedwith heated air outlets through which heated air is discharged atsubstantially the same temperature into said space, an air bloweroutside of said closet and space and operatively connected to said spaceand to said air inlet in the upper portion of the hollow member whichprojects above said closet, said blower being operative to supply fromsaid space to said air path, air to be heated and under a pressuregreater than the pressure of the products of combustion, means foroperating said blower in accordance with the rate of fuel input to saidfuel burning means, and an air bleed at the upper end of said air pathfor venting heated air from said air path during operation of said fuelburning means when said blower fails to operate in accordance with therate of fuel input to said fuel burning means.

7. A heating system for supplyingheated air to a space in a building tobe occupied by and for the comfort of human beings comprising avertically elongated closet arranged in said spac an elongated hollowmember vertically arranged in said closet in spaced relation to thewalls thereof and projecting thereabove, a metal chimney arranged insaid hollow member in spaced relation with the walls thereof andprojecting thereabove, said chimney extending upright from its lower endto and above the roof of the building and having an atmosphericdischarge external of said space. a combustion chamber in said lower endof said chimney, fuel burning means in said combustion chamberconstructed and arranged for burning fuel under natural draft operationand functioning to supply heated products of combustion to said chimney,said chimney providing a path for flow of the combustion products fromsaid combustion chamber to said atmospheric discharge, said hollowmember providing a path for flow of air in intimate heat exchangerelationship with said path for flow of the combustion products, saidair path being provided with its air inlet at its upper end and its airoutlet at its lower end and constructed so that all of the air whichenters said path traverses substantially all of said path and isdelivered therefrom at any one time during operation of said system at asubstantially uniform temperature, an air blower located outside of saidcloset and operatively connected to said space and to said air inlet ofsaid hollow member, said blower being operative to supply from saidspace to said air path, air to be heated and under a pressure greaterthan the pressure of the products of combustion. and means for operatingsaid blower during operation of said fuel burning means. said air outletof said air path opening into said closet and said closet being providedwith heated air outlets through all of which heated air is discharged atsubstantially the same temperature into said space.

8. A heating system for supplying heated air to a space in a building tobe occupied by and for the comfort of human beings comprising a verticalcloset arranged in said space, an elongated hollow member verticallyarranged in said closet in spaced relation to the walls thereof andprojecting thereabove, a metal chimney arranged in said hollow member inspaced relation with the walls thereof and projecting thereabove, saidchimney extending upright from its lower end to and above the roof ofthe building and having an atmospheric discharge external of said space,a combustion chamber in said lower end of said chimney and surroundedby'the lower end of said hollow member, fuel burning means in saidcombustion chamber constructed and arranged for burning fuel undernatural draft operation and functioning to supply heated products ofcombustion to said chimney, said chimney providing a path for flow ofthe combustion products from said combustion chamber to said atmosphericdischarge, said hollow member providing a path for flow of air inintimate countercurrent heat exchange relationship with said path forflow of the combustion products, said air path being provided with itsair inlet at its upper end and its air outlet at its lower end andconstructed so that all of the air which enters said path traversessubstantially all of said path and is delivered therefrom at any onetime during operation of said system at a substantially uniformtemperature, an air blower located outside of said closet and space andoperatively connected to said space and to said air inlet in the upperend of said hollow member, said blower being operative to supply fromsaid space to the upper end of said air path, air to be heated and undera pressure reater than the pressure of the products of combustion andmeans for operating said blower during operation of said fuel burningmeans, said air outlet in the lower end of said air path opening intosaid closet and said closet being provided with heated air outletsthrough which heated air is discharged at substantially the sametemperature into said space,

9. A heating system for supplying heated air to a space in a building tobe occupied by and for the comfort of human beings comprising avertically elongated closet arranged in said space and supported on thefloor thereof, an elongated hollow member vertically arranged in saidcloset in spaced relation to the walls thereof, a metal chimney arrangedin said hollow member in spaced relation with the walls thereof andprojecting thereabove, said chimney extending upright from its lower endto and above the roof of the building and having an atmosphericdischarge external of said space, a combustion chamber in said lower endof said chimney, fuel burning means in said combustion chamberconstructed and arranged for burning fuel under natural draft operationand functioning to supply heated products of combustion to said chimney,said chimney providing a path for flow of the combustion products fromsaid combustion chamber to said atmospheric discharge, said hollowmember providing a path for flow of air in intimate countercurrent heatexchange relationship with said path for flow of the combustionproducts, said ai path being provided with its air inlet at its upperend and its air outlet at its lower end and constructed so that all ofthe air which enters said path traverses substantially all of said pathand is delivered therefrom at any one time during operation of saidsystem at a substantially uniform temperature, an air blower outside ofsaid closet and operatively connected to said space and to said airinlet in the upper end of said hollow member, said blower beingoperative to supply from said space to the upper end of said air path,air to be heated and under a pressure greater than the pressure of theproducts of combustion, means for operating said blower during operationof said fuel burning means above a pilot fire rate, said outlet in thelower end of said air path opening into said closet and said closetbeing provided with heated air outlets through which heated air isdischarged at substantially the same temperature into said space, and athermostatically controlled air bleed at the upper end of said air pathfor venting heated air therefrom when said blower fails to operateduring operation of said fuel burning means above a pilot fire rate.

10. A heating system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged spaced metal pipes, said pipes having a lengthmany times greater than the diameter thereof, said pipes being securedrelative to each other so as to form a unit, one of said pipes forming achimney and extending upright from its lower end to and above the roofof the building and having an atmospheric discharge external of saidspace, a combustion chamber in said lower end of said chimney, fuelburning means in said combustion chamber constructed and arranged forburning fuel under natural draft operation and functioning to supplyheated products of combustion to said chimney, said chimney providing apath for fiow of the combustion products from said combustion chamber tosaid atmospheric discharge, said combustion chamber being arrangedrelative to said chimney so that the heated products of combustiongenerated in said combustion chamber are supplied to said chimney at atemperature of the order of that at which combustion occurs in saidcombustion chamber, the other of said pipes providing a unidirectionalpath for flow of air in intimate countercurrent heat exchangerelationship with the path for flow of the combustion products upwardlythrough said chimney, said air path being provided with its air inlet atits upper end and its air outlet at its lower end and constructed sothat all of the air which enters said path traverses substantially allof said path and is delivered therefrom at any one time during operationof said system at a substantially uniform temperature, a bloweroperatively connected to said air inlet opening and to said space. saidblower being operative during operation of said fuel burning means tosupply from said space through said inlet opening to said air path, airto be heated and under a pressure greater than the pressure of theproducts of combustion in said chimney, said unit being suspended abovethe floor of said space and having said air outlet arranged to dischargeheated air downwardly toward the floor of said space.

11. A heating system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged, spaced elongated metal pipes, said pipes havinga length many times greater than the diameter thereof, said pipes beingsecured relative to each other so as to form a unit, one of said pipesforming a chimney and extending upright from its lower end to and abovethe roof of the building and having an atmospheric discharge external ofsaid space, a combustion chamber in saidlower end of said chimney, fuelburning means in said combustion chamber constructed and arranged forburning fuel under natural draft operation and functioning to supplyheated products of combustion to said chimney, said combustion chamberbeing arranged relative to said chimney so that the heated products ofcombustion generated in said combustion chamber are supplied to saidchimney at a temperature of the order of that at which combustion occursin said combustion chamber, said chimney providing a path for flow ofthe combustion products from said combustion chamber to said atmosphericdischarge, the other of said pipes providing a unidirectional path forflow of air in intimate countercurrent heat exchange relationship withthe path for flow of the combustion products upwardly through saidchimney, said air path being provided with its air inlet at its upperend and its air outlet at its lower end and contsructed so that all ofthe air which enters said path traverses substantially all of said pathand is delivered therefrom at any one time during operation of saidsystem at a substantially uniform temperature, a blower operativelyconnected to said air inlet opening and to said space, said blower beingoperative during operation of said fuel burning means to supply fromsaid space'through said air inlet opening to said air path, air to beheated and under a pressure greater than the pressure of the products ofcombustion in said chimney, said air path having an opening at the upperend thereof operable when said blower is not operating for ventingheated air from said air path.

12. A heating system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged spaced metal pipes, said pipes having a lengthmany times greater than the diameter thereof, said pipes being securedrelative to each other so as to form a unit, one of said pipes forming achimney and extending upright from its lower end to and above the roofof the building and havfng an atmospheric discharge external of saidspace, a combustion chamber in said lower end of said chimney, fuelburning means in said combustion chamber constructed and arranged forburning fuel under natural draft operation and functioning to supplyheated products of combustion to sad chimney, said combustion chamberbeing arranged relative to said chimney so that the heated products ofcombustion generated in said combustion chamber are supplied to saidchimney at a temperature of the order of that at which combustion occursin said combuston chamber, said chimney providing a path for flow of thecombustion products from said combustion chamber to said atmosphericdischarge, the other of said pipes providing a unidirectional path forflow of a r in intimate countercurrent heat exchange relationship withthe path for flow of the combustion products upwardly through saidchimney, said air path being provided with its air inlet at its upperend and its air outlet at its lower end and constructed so that allotthe air which enters said path traverses substantially all of said pathand is delivered therefrom at any one time during operat'on of saidsystem at a substantially uniform temperature, a blower operativelyconnected to said air inlet opening and to said space, said blower beingoperative during operation of said fuel burning means to supply fromsaid space through said air inlet open'ng to said air path, air to beheated and under a pressure greater than the pressure of the products ofcombustion in said chimney, said air path being of suilicient length sothat the forced flow of air therethrough due to said blower will coolthe products of combustion from combustion temperature down to at least300 F. during normal operation of said heating system, and a verticallyelongated closet in which the lower ends of said pipes are arranged andinto which heated air is delivered from said heated air discharge outletof said air path, said closet being arranged in said space and beingprovided with warm air outlets through which heated air is discharged atsubstantially the same temperature into said space,

13. A heating system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged spaced metal pipes, said pipes having a lengthmany times greater than the diameter thereof, said pipes being securedrelative to each other so as to form a unit, one of said pipes forming achimney and extending upright from its lower end to and above the roofof the building and having an atmospheric discharge external of saidspace, a combustion chamber in said lower end of said chimney, fuelburning means in said combustion chamber constructed and arranged forburning fuel under natural draft operation and functioning to supplyheated products of combustion to said chimney, said combustion chamberbeing arranged relative to said chimney so that the heated products ofcombustion generated in said combustion chamber are supplied to saidchimney at a temperature of the order of that at which combustion occursin said combustion chamber, said chimney providing a path for flow ofthe combustion products from said combustion chamber to said atmosphericdischarge, the other of said pipes providing a unidirectional path forflow of air around and in intimate countercurrent heat exchangerelationship with the path for flow of the combustion products upwardlythrough said chimney, said air path being provided with its air inlet atits upper end and its air outlet at its lower end and constructed sothat all of the air which enters said path traverses substantially allof said path and is delivered therefrom at any one time during operationof said system at a substantially uniform temperature, a bloweroperatively connected to said air inlet opening and to said space, saidblower being operative during operation of said fuel burning means abovea pilot fire rate to supply from said space through said air inletopening, to said air path, air to be heated and under a pressure greaterthan the pressure of the products of combustion in said chimney, saidair path being of suflicient length so that the forced flow of airtherethrough will cool the products of combustion from combustiontemperature down to at least 300 F, during normal operation of saidheating system, said air path having an opening at the upper end thereoffor venting heated air therefrom when said blower fails to operateduring operation of said fuel burning means above a pilot fire rate.

14. A heating" system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged spaced metal pipes, said pipes having a lengthmany times greater than the diameter thereof, said pipes being securedrelative to each other so as to form a unit, one of said pipes forming achimney and extending upright from its lower end to and above the roofof the building and having an atmospheric discharge external of saidspace, a combustion chamber in said lower end of said chimney, fuelburning means in said combustion chamber constructed and arranged forburning fuel under natural draft operation and functioning to supplyheated products of combustion to said chimney, said combustion chamberbeing arranged relative to said chimney so that the heated products ofcombustion generated in said combustion chamber are supplied to saidchimney at a tempera ture of the order of that at which combustionoccurs in said combustion chamber, said chimney providing a path forflow of the combustion products from said combustion chamber to saidatmospheric discharge, the other of said pipes providing aunidirectional path for flow of air surrounded by and in intimatecountercurrent heat exchange relationship with the path for flow of thecombustion products upwardly through said chimney, said air path beingprovided with its air inlet at its upper end and its air outlet at itslower end and constructed so that all of the air which enters said pathtraverses substantially all of said path and is delivered therefrom atany one time during operation of said system at a substantially uniformtemperature, a blower operatively connected to said air inlet openingand to said space, said blower being operative during operation of saidfuel burning means above a pilot fire rate to supply from said spacethrough said air inlet opening, to said air path, air to be heated andunder a pressure greater than the pressure of the products of combustionin said chimney, said air path being of sufilcient length so that theforced flow of air therethrough will cool the products of combustionfrom combustion temperature down to at least 300 F. during nor maloperation of sa d heating system, said air path having an opening at theupper end thereof for venting heated air therefrom when said blowerfails to operate during operation of said fuel burning means above apilot fire rate.

15. A heating system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged spaced pipes, said pipes having a length manytimes greater than the diameter thereof, said pipes being securedrelative to each other so as to form a unit, said unit being supportedin said space adjacent the upper portion thereof and so as not to occupyspace adjacent thefioor of said space, one of said pipes being formed ofmetal'and forming a chimney and extending upright from its lower end toand above the roof of the building and having an atmospheric dischargeexternal ofsaid space, a combustion chamber in said lower end of saidchimney, fuel burning means in said combustion chamber constructed andarranged for burning fuel under natural draft operation and functioningto supply heated products of combustion to said chimney, said chimneyproviding a path for flow of the combustion products from saidcombustion chamber to said atmospheric discharge, the other of saidpipes providing a path for flow of air in intimate countercurrent heatexchange relationship with the path for flow of the combustion productsupwardly through said chimney, said air path being provided with its airinlet at its upper end and its air outlet at its lower end andconstructed so that all of the air which enters said path traversessubstantially all of said path I and is deliveied therefrom at any onetime during operation of said system at a substantially uniformtemperature, a blower operatively connected to said air inlet openingand to said space,

said blower being operative to supply from said outlet arranged todischarge heated air downwardly toward the floor above which it issupported.

16. A heating system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged spaced pipes, said pipes having a length manytimes greater than the diameter thereof, said pipes being securedrelative to each other so as to form a unit, one of said pipes beingformed of metal and forming a chimney and extending upright from itslower end to and above the roof of the building and having anatmospheric discharge external of said space, a combustion chamber insaid lower end of said chimney, fuel burning means in said combustionchamber constructed and arranged for burning fuel under natural draftoperation and functioning to supply heated products of combustion tosaid chimney, said chimney providing a path for flow of the combustionproducts from said combustion chamber to said atmospheric discharge, theother of said pipes providing a path for flow of air in intimatecountercurrent heat exchange relationship with the pathfor flow of thecombustion products upwardly through said chimney, said air path beingprovided with its air inlet at its upper end and its air outlet at itslower end and constructed so that all of the air which.

enters said path traverses substantially all of said path and isdelivered therefrom at any one time during operation of said system at asubstantially uniform temperature, a blower operatively connected tosaid air inlet opening and to said space, said blower being operativeduring operation of said fuel burning means above a pilot fire rate, tosupply from said space through said air inlet opening to said air path,air to be.

heated and under a pressure greater than the pressure of the products ofcombustion in said chimney, said air path having an opening at the upperend thereof operable when said blower is not operating during operationof said fuel burning means above a pilot fire rate for venting heatedair from said air path.

17. A heating system for supplying heated air to a space in a buildingfor human occupancy comprising a pair of vertically disposedtelescopically arranged spaced pipes, said pipes having a length manytimes greater than the diameter thereof, said pipes being securedrelative to each other so as to form a unit, one of said pipes beingformed of metal and forming a chimney and extending upright from itslower end to and above the roof of the building and having anatmospheric discharge external of said space, a combustion chamber insaid lower end of said chimney, fuel burning means in said combustionchamber constructed and arranged for burning fuel under natural draftoperation and functioning to supply heated products of combustion tosaid chimney, said combustion chamber being arranged relative to saidchimney so that the heated products of combustion generated in saidcombustion chamber are supplied to said chimney at a temperature of theorder of that at which combustion occurs in said combustion chamber,said chimney providing a path for flow of the combustion products fromsaid combustion chamber to said atmospheric discharge, the other of saidpipes providing a path for flow of air in intimate heat exchangerelationship with the path for flow of the combustion products upwardlythrough said chimney, said air path being provided with its air inlet atits upper end and its air outlet at its lower end and constructed sothat all of the air which enters said path traverses substantially allof said path and is delivered therefrom at any one time during operationof said system at a substantially uniform temperature, a bloweroperatively connected to said air inlet opening and to said space, saidblower being operative to supply from said space through said air inletopening to said air path, air to be heated and under a pressure greaterthan the pressure of the products of combustion in said chimney, and acloset which extends vertically a distance equal to or more than theheight of one floor of said heated space and in which the lower ends ofsaid pipes are arranged, said heated air outlet opening into said closetand said closet being provided with heated air outlets through whichheated air is discharged at substantially the same temperature into saidspace.

MORITZL. MUELLER.

